Physical Review D, cilt.111, sa.1, 2025 (SCI-Expanded)
Using (27.12±0.14)×108 ψ(2S) events collected by the BESIII detector operating at BEPCII, we search for the decay ηc(2S)→pp¯ via the process ψ(2S)→γηc(2S) and only find a signal with a significance of 1.7σ. The upper limit of the product branching fraction at the 90% confidence level is determined to be B(ψ(2S)→γηc(2S))×B(ηc(2S)→pp¯)<2.4×10-7. The branching fractions of χcJ→pp¯ (J=0,1,2) are also measured to be B(χc0→pp¯)=(2.51±0.02±0.08)×10-4, B(χc1→pp¯)=(8.16±0.09±0.25)×10-4, and B(χc2→pp¯)=(8.33±0.09±0.22)×10-4, where the first uncertainty is statistical and the second systematic.